A variety of eyepiece optical members that can guide image light from a compact display panel with a light guide prism to allow observation of the image light as a magnified virtual image have been proposed (for example, see JP 2012-203113 A (PTL 1)). Such an eyepiece optical member can be used as a wearable device, such as a head-mounted display (HMD), by being mounted in a display device that can be worn on the observer's head.
In such an eyepiece optical member, a portion of the light guide prism is sometimes exposed from the housing to reduce size. When exposing a portion of the light guide prism, the front of the light guide prism that is exposed could be covered by a protective cover secured to the light guide prism.